A brain coral infected with Stony Coral Tissue Loss Disease (SCTLD) in the Florida Keys National Marine Sanctuary in April 2018.

Porites and Acropora coral species in reef flat pools in the National Park of American Samoa on Ofu, Manuʻa Islands Group, American Samoa.

Dive operations with National Park Service and the National Park of American Samoa installing tide, wave, temperature, and salinity sensors on the fore reef in NPSA off the south shore of Ofu, Manuʻa.

A coral reef in the Turks and Caicos Islands dominated by the weedy coral species, Porites astreoides. The relative dominance of this taxa has increased throughout the western Atlantic.

Two red sea urchins (Mesocentrotus franciscanus) sit on the deck of the R/V Falkor. These sea urchins were collected during the #HuntingBubbles research cruise led by the USGS and Schmidt Ocean Institute, which focused on exploring and understanding methane seeps and the communities that depend on them along the Cascadia Margin.

The USGS is conducting research to guide the recovery of the threatened Elkhorn coral, Acropora palmata, in Dry Tortugas National Park and throughout the western Atlantic.

A reef in the Florida Keys National Marine Sanctuary with little living coral and extensive bioerosion. Photo taken under research permit number FKNMS-2016-085-A1.

Research Oceanographer Lauren Toth and student volunteer Liz Whitcher drill a coral-reef core from a reef off Key West, Florida, in the Florida Keys National Marine Sanctuary.

Relict Holocene coral-reef framework in the Florida Keys.

U.SGS's Coral Assessment Network (USGS-CAN) provides data on coral-growth (calcification) rates throughout the Florida Keys. Pictured here is one of 30 stations located in in Dry Tortugas National Park.

Underwater photograph showing corals in Tāfeu Cove, National Park of American Samoa, north shore of Tutuila Island, American Samoa.

Lush thicket of staghorn coral in the Dry Tortugas National Park

Cerulean damselfish dart around lettuce coral off the Cape Range National Park along the Ningaloo Coast in Western Australia.

Healthy Elkhorn coral (Acropora palmata) near unpopulated Buck Island, U.S. Virgin Islands.

A diver peeks from behind a badly bleached coral in the Florida Keys National Marine Sanctuary in October 2015.

Underwater image of a wave breaking over a coral reef on Kwajalein Atoll in the Republic of the Marshall Islands.

USGS research geologist Curt Storlazzi free dives in order to set an instrument on the reef off Kauaʻi, Hawaiʻi in March 2015.

A USGS diver beside a Massive Starlet (Siderastrea siderea) coral colony in Dry Tortugas National Park. Scientists used a core from this coral to reconstruct ocean temperatures going back to 1837.

Coral Culture Facility, Charleston, SC

A researcher surveys the progression of stony coral tissue loss disease in Florida Keys National Marine Sanctuary.

Coral Assay Video Image

MUSC Coral Project

MUSC Coral Project

MUSC Coral Project

MUSC Coral Project

Larvae Nursery

Larvae Nursery

Larvae Nursery

Larvae Nursery

Larvae Nursery

Brain coral releasing gamete bundles during spawning

A thicket of Acropora cervicornis colonies (hermaphrodites) release gamete bundles

Coral releasing gamete bundles during spawning

Coral releasing gamete bundles during spawning

Coral gamete bundles collected in a sample tube during annual spawning event

Coral gamete bundles collected in a sample tube during annual spawning event

Coral polyps with gamete bundles near the mouth opening preparing for release, known as "setting"

Coral gamete bundles collected in a sample tube during annual spawning event

Gamete bundles in a collection tube begin to separate into their composite eggs and sperm

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral releasing gamete bundles during spawning

Gamete bundles break down into their composite eggs and sperm in the lab

Coral polyps with gamete bundles near the mouth opening preparing for release, known as "setting"

Gamete bundles break down into their composite eggs and sperm in the lab

Gamete bundles break down into their composite eggs and sperm in the lab

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Gamete bundles break down into their composite eggs and sperm in the lab

Coral polyps with gamete bundles near the mouth opening preparing for release, known as "setting"

Coral polyps with gamete bundles near the mouth opening preparing for release, known as "setting"

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

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Coral releasing gamete bundles during spawning

Coral polyps with gamete bundles near the mouth opening preparing for release, known as "setting"

Coral polyps with gamete bundles near the mouth opening preparing for release, known as "setting"

Coral releasing gamete bundles during spawning

Coral releasing gamete bundles during spawning

Coral polyps with gamete bundles near the mouth opening preparing for release, known as "setting"

A male colony of Montastrea cavernosa (gonochoric) releases sperm during annual spawn event

A female colony of Montastrea cavernosa (gonochoric) releases eggs during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Scientists collect released gamete bundles form a captive coral colony

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

A colony of Pseudodpiloria strigosa (hermaphrodite) releases gamete bundles

Brain coral releasing gamete bundles during spawning

Coral gamete bundles approach the polyp mouth before being released during the annual spawning event

Coral gamete bundles approach the polyp mouth before being released during the annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning

Coral releasing gamete bundles during spawning

Coral gamete bundles approach the polyp mouth before being released during the annual spawning event

A colony of Acropora palmata releases its gamete bundles during annual spawning event

Coral egg and sperm bundles captured in a sample tube during annual spawning event

Brain coral releasing gamete bundles during spawning

Brain coral releasing gamete bundles during spawning